Children in America's inner cities are at risk of exposure to multiple known and potential neurodevelopmental toxicants: pesticides in homes, polychlorinated biphenyls (PCBs) in contaminated fish and lead. The goal of the Mount Sinai Center for Children's Environmental Health and Disease Prevention Research will be to identify, characterize, elucidate and prevent neurodevelopmental deficits that result from exposures to environmental toxicants in the inner city. Project 1, a community-based prevention research trial, with intervention and control arms, will be undertaken in East Harlem, New York City, in partnership with a network of community-based organizations and a Community Advisory Board. The goal will be to reduce exposures to pesticides, PCBs and other developmental toxicants in households. In intervention households, recruited through Boriken Neighborhood Health Center, Integrated Pest Management and dietary modification will be applied. Control households will be an East Harlem subset of Project 2 families. Outcome evaluation in both groups will consist of baseline and follow-up measures of pesticide levels in house dust; pesticide metabolite levels in urine; roach infestation levels; and frequency of consumption of local fish. In years 3 and 4, lessons learned in household intervention will be extended broadly through East Harlem. Project 2 will be a prospective epidemiologic study of an ethnically diverse birth cohort of infants born at Mount Sinai. It will asses whether in utero exposures to pesticides and other toxicants are associated with developmental delays. Project 3 will study genetic polymorphisms in the enzymes that activate and detoxify organophosphates and other pesticides in the population of mothers and infants enrolled in Project 2. Project 4, a retrospective study of African-Americans enrolled in the Collaborative Perinatal Project, will assess whether in utero exposures to PCBs are associated with neuropsychological dysfunction in adolescent or adult life. Project 5 will examine the mechanisms by which environmental toxicants affect neuroendocrine development. Experiments in a female rat model will characterize interactions between toxicants and hypothalamic GnRH neurosecretory neurons, key regulators or reproductive development. The Center will contain Facilities Cores in Exposure Assessment and Biostatistics/Data Management, as well as an Administration Core.